Vascular remodeling and protease inhibition--bench to bedside

Serum levels of Matrix Metalloproteinases (MMPs) in patients undergoing endovascular intervention for peripheral arterial disease

OBJECTIVES

Matrix metalloproteinases (MMPs) play a significant role in the development and progression of atherosclerotic vascular disease. The purpose of this study was to measure and document the profile of plasma circulating MMPs in patients with peripheral arterial disease (PAD) undergoing endovascular revascularization.

METHODS

This was a single centre prospective observational study with 80 patients with PAD enrolled. They underwent percutaneous balloon angioplasty and/or angioplasty with stent. Exclusion criteria were acute limb ischemia, active inflammation, wet gangrene, liver disease, end stage renal failure and cancer. Patients that underwent open or hybrid (open and endovascular) approach, were also excluded from the study. Venous blood samples were taken preoperatively, 24 hours and 6 months postoperatively. The values of MMP-2, MMP-3, MMP-7, MMP-9 and their inhibitors (Tissue Inhibitor of metalloproteinases, TIMP), TIMP-1 and TIMP-2 were measured.

RESULTS

The mean age was 67.1 years and 66 of them (82.5%) were male. During the clinical follow up (mean 35.8% months), 12 patients died (16.4%), 15 (20.5%) of them had a major adverse limb event (MALE) and 14 (19.2%) of them had a major adverse cardiovascular event (MACE). There was a statistically significant raise in the values of MMP-2. MMP-3 and MMP-7 at 6 months postoperatively, when compared to the preoperative and 24 hours postoperative values. There was no correlation of MMP and TIMP values with mortality, MALE and MACE events.

CONCLUSIONS

The present single-centre prospective study documented increased circulating levels of MMPs post-operatively in PAD patients undergoing endovascular treatment. Vascular trauma caused by angioplasty, could trigger expression of MMPs and TIMPs, but the absence of any association with clinical complications requires further investigation.

Content of matrix metalloproteinases in the blood of hypertensive patients with a high cardiovascular risk receiving statin therapy

Aim. To compare the effect of atorvastatin and rosuvastatin as part of complex therapy in patients with hypertension (HTN) with a high cardiovascular risk on the level of matrix metalloproteinases -1, -9 (MMP-1, MMP-9) and tissue inhibitors of metalloproteinases -1, -4 (TIMP-1, TIMP-4).

Material and methods. The study included 140 hypertensive patients who received atorvastatin (Liprimar) 20 mg/day in addition to antihypertensive therapy for a year, which was later replaced by rosuvastatin (Rosucard) in the following doses: 10 mg/day (n=96), 20 mg/day (n=24), 40 mg/day (n=26). Patients underwent standard clinical and paraclinical investigations. In the blood serum of patients, the levels of MMP-1, MMP-9 and TIMP-1, TIMP-4 were determined.

Results. Patients who used rosuvastatin at a dose of 40 mg/day had a more pronounced decrease in MMP-1 than those treated with rosuvastatin at a dose of 10 and 20 mg/day (p<0,05), while there were no differences in MMP-1 when using low and medium doses. Rosuvastatin had a less pronounced effect on MMP-9 than on MMP-1, while increasing the dose of rosuvastatin did not affect the intensity of MMP-9 reduction (p>0,05). The content of TIMP-1 and TIMP-4 increased when taking rosuvastatin, while a more pronounced dose-dependent increase in TIMP-1 was observed with rosuvastatin 20 mg/day and 40 mg/day. In addition, the largest increase in TIMP-4 was observed when using rosuvastatin at a dose of 40 mg/day. Atorvastatin had no significant effect on MMP-1 and MMP-9, as well as TIMP-1 and TIMP-4.

Conclusion. Long-term rosuvastatin therapy (10 mg/day, 20 mg/day, 40 mg/day) as part of the complex therapy of cardiovascular patients affects the metabolism of vascular wall elastin and collagen, reducing the level of MMP-1, MMP-9 and increasing the content of TIMP-1, TIMP-4 in the blood.

Matrix Metalloproteinases: From Molecular Mechanisms to Physiology, Pathophysiology, and Pharmacology

The first matrix metalloproteinase (MMP) was discovered in 1962 from the tail of a tadpole by its ability to degrade collagen. As their name suggests, matrix metalloproteinases are proteases capable of remodeling the extracellular matrix. More recently, MMPs have been demonstrated to play numerous additional biologic roles in cell signaling, immune regulation, and transcriptional control, all of which are unrelated to the degradation of the extracellular matrix. In this review, we will present milestones and major discoveries of MMP research, including various clinical trials for the use of MMP inhibitors. We will discuss the reasons behind the failures of most MMP inhibitors for the treatment of cancer and inflammatory diseases. There are still misconceptions about the pathophysiological roles of MMPs and the best strategies to inhibit their detrimental functions. This review aims to discuss MMPs in preclinical models and human pathologies. We will discuss new biochemical tools to track their proteolytic activity in vivo and ex vivo, in addition to future pharmacological alternatives to inhibit their detrimental functions in diseases. SIGNIFICANCE STATEMENT: Matrix metalloproteinases (MMPs) have been implicated in most inflammatory, autoimmune, cancers, and pathogen-mediated diseases. Initially overlooked, MMP contributions can be both beneficial and detrimental in disease progression and resolution. Thousands of MMP substrates have been suggested, and a few hundred have been validated. After more than 60 years of MMP research, there remain intriguing enigmas to solve regarding their biological functions in diseases.

Applications of Extracellular Vesicles in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a localized expansion of the abdominal aorta which can lead to lethal complication as the rupture of aortic wall. Currently there is still neither competent method to predict the impending rupture of aneurysm, nor effective treatment to arrest the progression of small and asymptomatic aneurysms. Accumulating evidence has confirmed the crucial role of extracellular vesicles (EVs) in the pathological course of AAA, acting as important mediators of intercellular communication. Given the advantages of intrinsic targeting properties, lower toxicity and fair stability, EVs show great potential to serve as biomarkers, therapeutic agents and drug delivery carriers. However, EV therapies still face several major challenges before they can be applied clinically, including off-target effect, low accumulation rate and rapid clearance by mononuclear phagocyte system. In this review, we first illustrate the roles of EV in the pathological process of AAA and evaluate its possible clinical applications. We also identify present challenges for EV applications, highlight different strategies of EV engineering and constructions of EV-like nanoparticles, including EV display technology and membrane hybrid technology. These leading-edge techniques have been recently employed in multiple cardiovascular diseases and their promising application in the field of AAA is discussed.

MK2206 attenuates atherosclerosis by inhibiting lipid accumulation, cell migration, proliferation, and inflammation

Cardiovascular disease is a common comorbidity in patients with cancer, and the main leading cause of noncancer-related deaths in cancer survivors. Considering that current antitumor drugs usually induce cardiovascular injury, the quest for developing new antitumor drugs, especially those with cardiovascular protection, is crucial for improving cancer prognosis. MK2206 is a phase II clinical anticancer drug and the role of this drug in cardiovascular disease is still unclear. Here, we revealed that MK2206 significantly reduced vascular inflammation, atherosclerotic lesions, and inhibited proliferation of vascular smooth muscle cell in ApoE^-/- mice in vivo. We demonstrated that MK2206 reduced lipid accumulation by promoting cholesterol efflux but did not affect lipid uptake and decreased inflammatory response by modulating inflammation-related mRNA stability in macrophages. In addition, we revealed that MK2206 suppressed migration, proliferation, and inflammation in vascular smooth muscle cells. Moreover, MK2206 inhibited proliferation and inflammation of endothelial cells. The present results suggest that MK2206, as a promising drug in clinical antitumor therapy, exhibits anti-inflammatory and antiatherosclerotic potential. This report provides a novel strategy for the prevention of cardiovascular comorbidities in cancer survivors.

Toward the Effective Bioengineering of a Pathological Tissue for Cardiovascular Disease Modeling: Old Strategies and New Frontiers for Prevention, Diagnosis, and Therapy

Cardiovascular diseases (CVDs) still represent the primary cause of mortality worldwide. Preclinical modeling by recapitulating human pathophysiology is fundamental to advance the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and treatment. In silico, in vivo, and in vitro models have been applied to dissect many cardiovascular pathologies. Computational and bioinformatic simulations allow developing algorithmic disease models considering all known variables and severity degrees of disease. In vivo studies based on small or large animals have a long tradition and largely contribute to the current treatment and management of CVDs. In vitro investigation with two-dimensional cell culture demonstrates its suitability to analyze the behavior of single, diseased cellular types. The introduction of induced pluripotent stem cell technology and the application of bioengineering principles raised the bar toward in vitro three-dimensional modeling by enabling the development of pathological tissue equivalents. This review article intends to describe the advantages and disadvantages of past and present modeling approaches applied to provide insights on some of the most relevant congenital and acquired CVDs, such as rhythm disturbances, bicuspid aortic valve, cardiac infections and autoimmunity, cardiovascular fibrosis, atherosclerosis, and calcific aortic valve stenosis.

Collagen analysis with mass spectrometry

Mass spectrometry-based techniques can be applied to investigate collagen with respect to identification, quantification, supramolecular organization, and various post-translational modifications. The continuous interest in collagen research has led to a shift from techniques to analyze the physical characteristics of collagen to methods to study collagen abundance and modifications. In this review, we illustrate the potential of mass spectrometry for in-depth analyses of collagen.

Plasma levels of matrix metalloproteinase-9 are elevated in individuals with hypertensive crisis

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) participates in the degradation of components of the extracellular matrix and it is involved in vascular remodeling and vasomotor changes. The aim of this study was to investigate the plasma levels of MMP-9 in acute vascular alterations due to hypertensive crisis.

METHODS

This cross-sectional study was performed in 40 normotensive (NT) and 58 controlled hypertensive subjects (CHyp) followed up in outpatient clinic. Moreover, 57 patients with hypertensive emergency (HypEmerg) and 43 in hypertensive urgency (HypUrg), seen in emergency department, were also included. Hypertensive crisis was divided into HypEmerg, which was characterized by levels of systolic blood pressure (BP) ≥ 180 mmHg and/or diastolic BP ≥ 120 mmHg complicated with target-organ damage (TOD), and HypUrg, defined by BP elevation without TOD. Univariate and multivariate regression analysis was performed to identify the influence of independent variables on MMP-9 levels. A p-value < 0.05 was considered statistically significant.

RESULTS

The mean age was 43.5 years in the NT group (11 men); 57.7 years in the CHyp group (29 men); 59.4 years in the HypUrg group (21 men) and 62.4 years in the HypEmerg group (31 men). The age was statistically different in the NT group compared to other 3 groups. The mean BP was 116.5 ± 13.9/72.4 ± 10.6 mmHg for NT, 123.2 ± 12.6/79 ± 9.2 for CHyp, 194.1 ± 24.3/121.4 ± 17.3 for HypUrg and 191.6 ± 34.3/121.7 ± 18.8 mmHg for HypEmerg, respectively (p-value< 0.0001 between groups). MMP-9 levels were statistically different between the HypEmerg (2.31 ± 0.2 ng/mL) and HypUrg groups (2.17 ± 0.3 ng/mL) compared to the NT (1.94 ± 0.3 ng/mL) (p-value < 0.01 and p-value < 0.05, respectively) and CHyp groups (1.92 ± 0.2 ng/mL) (p-value < 0.01). Uric acid was the only independent variable for predicting MMP-9 levels (p-value = 0.001).

CONCLUSION

MMP-9 concentrations are significantly higher in the hypertensive crisis groups (urgency and emergency) compared to the control groups. Therefore, MMP-9 may be a biomarker or mediator of pathophysiologic pathways in cases of acute elevations of blood pressure.

Up-regulation of collagen proteins in colorectal liver metastasis compared with normal liver tissue

Changes to extracellular matrix (ECM) structures are linked to tumor cell proliferation and metastasis. We previously reported that naturally occurring peptides of collagen type I are elevated in urine of patients with colorectal liver metastasis (CRLM). In the present study, we took an MS-based proteomic approach to identify specific collagen types that are up-regulated in CRLM tissues compared with healthy, adjacent liver tissues from the same patients. We found that 19 of 22 collagen-α chains are significantly up-regulated (p < 0.05) in CRLM tissues compared with the healthy tissues. At least four collagen-α chains were absent or had low expression in healthy colon and adjacent tissues, but were highly abundant in both colorectal cancer (CRC) and CRLM tissues. This expression pattern was also observed for six noncollagen colon-specific proteins, two of which (CDH17 and PPP1R1B/DARP-32) had not previously been linked to CRLM. Furthermore, we observed CRLM-associated up-regulation of 16 proteins (of 20 associated proteins identified) known to be required for collagen synthesis, indicating increased collagen production in CRLM. Immunohistochemistry validated that collagen type XII is significantly up-regulated in CRLM. The results of this study indicate that most collagen isoforms are up-regulated in CRLM compared with healthy tissues, most likely as a result of an increased collagen production in the metastatic cells. Our findings provide further insight into morphological changes in the ECM in CRLM and help explain the finding of tumor metastasis-associated proteins and peptides in urine, suggesting their utility as metastasis biomarkers.

MMP-2 and TIMP-2 in Patients with Heart Failure and Chronic Kidney Disease

The aim of the study was to assess MMP-2 (matrix metalloproteinase-2) and TIMP-2 (tissue inhibitor of metalloproteinase-2) serum levels in patients with diverse types of heart failure (HF) and chronic kidney disease (CKD).

101 patients with chronic HF were enrolled. Each patient has assessed the serum levels of MMP-2, TIMP-2, and NT-proBNP. Patients were initially classified into 2 groups based on their LVEF. 43 patients were classified into the HFREF group (HF with Reduced Ejection Fraction) and 58 characterized as HFPEF (HF with Preserved Ejection Fraction). Next, all patients were subdivided into 4 groups according to the degree of diastolic dysfunction.

38 patients with CKD were classified into HF/CKD(+) group. The HF/CKD(-) (HF without CKD) group comprised 61 patients.

This study provides original data on positive correlation between ejection fraction and MMP-2 levels in all patients with heart failure. Elevated levels of MMP-2 and TIMP-2 were found in serum from patients with chronic kidney disease; in addition, serum levels of MMP-2 were correlated with the degree of kidney failure. In all groups of patients there was positive correlation between MMP-2 and TIMP-2. Among patients with heart failure etiology was not related to MMP-2 and TIMP-2 serum levels.

Tissue Inhibitor of Metalloproteinase-3 (TIMP-3) induces FAS dependent apoptosis in human vascular smooth muscle cells

Over expression of Tissue Inhibitor of Metalloproteinases-3 (TIMP-3) in vascular smooth muscle cells (VSMCs) induces apoptosis and reduces neointima formation occurring after saphenous vein interposition grafting or coronary stenting. In studies to address the mechanism of TIMP-3-driven apoptosis in human VSMCs we find that TIMP-3 increased activation of caspase-8 and apoptosis was inhibited by expression of Cytokine response modifier A (CrmA) and dominant negative FAS-Associated protein with Death Domain (FADD). TIMP-3 induced apoptosis did not cause mitochondrial depolarisation, increase activation of caspase-9 and was not inhibited by over-expression of B-cell Lymphoma 2 (Bcl2), indicating a mitochondrial independent/type-I death receptor pathway. TIMP-3 increased levels of the First Apoptosis Signal receptor (FAS) and depletion of FAS with shRNA showed TIMP-3-induced apoptosis was FAS dependent. TIMP-3 induced formation of the Death-Inducing Signalling Complex (DISC), as detected by immunoprecipitation and by immunofluorescence. Cellular-FADD-like IL-1 converting enzyme-Like Inhibitory Protein (c-FLIP) localised with FAS at the cell periphery in the absence of TIMP-3 and this localisation was lost on TIMP-3 expression with c-FLIP adopting a perinuclear localisation. Although TIMP-3 inhibited FAS shedding, this did not increase total surface levels of FAS but instead increased FAS levels within localised regions at the cell surface. A Disintegrin And Metalloproteinase 17 (ADAM17) is inhibited by TIMP-3 and depletion of ADAM17 with shRNA significantly decreased FAS shedding. However ADAM17 depletion did not induce apoptosis or replicate the effects of TIMP-3 by increasing localised clustering of cell surface FAS. ADAM17-depleted cells could activate caspase-3 when expressing levels of TIMP-3 that were otherwise sub-apoptotic, suggesting a partial role for ADAM17 mediated ectodomain shedding in TIMP-3 mediated apoptosis. We conclude that TIMP-3 induced apoptosis in VSMCs is highly dependent on FAS and is associated with changes in FAS and c-FLIP localisation, but is not solely dependent on shedding of the FAS ectodomain.

Disruption of blood-brain barrier integrity in postmortem alcoholic brain: preclinical evidence of TLR4 involvement from a binge-like drinking model

Inflammatory cytokines and reactive oxygen species are reported to be involved in blood-brain barrier (BBB) disruption. Because there is evidence that ethanol (EtOH) induces release of free radicals, cytokines and inflammatory mediators we examined BBB integrity and matrix metalloproteinase (MMP) activity in postmortem human alcoholic brain and investigated the role of TLR4 signaling in BBB permeability in TLR4-knockout mice under a binge-like EtOH drinking protocol. Immunohistochemical studies showed reduced immunoreactivity of the basal lamina protein, collagen-IV and of the tight junction protein, claudin-5 in dorsolateral prefrontal cortex of alcoholics. There was also increased MMP-9 activity and expression of phosphorylated ERK1/2 and p-38. Greater number of CD45+ IR cells were observed associated with an enhanced neuroinflammatory response reflected by increased GFAP and Iba-1 immunostaining. To further explore effects of high EtOH consumption on BBB integrity we studied TLR4-knockout mice exposed to the drinking in the dark paradigm. Repetitive EtOH exposure in wild-type mice decreased hippocampal expression of laminin and collagen-IV and increased IgG immunoreactivity, indicating IgG extravasation. Western blot analysis also revealed increased MyD88 and p-ERK1/2 levels. None of these changes was observed in TLR4-knockout mice. Collectively, these findings indicate that chronic EtOH increases degradation of tight junctions and extracellular matrix in postmortem human brain and induces a neuroinflammatory response associated with activation of ERK1/2 and p-38 and greater MMP-9 activity. The EtOH-induced effects on BBB impairment are not evident in the hippocampus of TLR4-knockout mice, suggesting the involvement of TLR4 signaling in the underlying mechanism leading to BBB disruption in mice.

Alisol A 24-Acetate, a Triterpenoid Derived from Alisma orientale, Inhibits Ox-LDL-Induced Phenotypic Transformation and Migration of Rat Vascular Smooth Muscle Cells through Suppressing ERK1/2 Signaling

Alisol A 24-acetate, a triterpenoid extracted from Alisma orientale, has shown antiatherosclerotic actions. The purpose of this study was to evaluate the inhibition of alisol A 24-acetate on oxidized low-density lipoprotein (Ox-LDL)-induced phenotypic transformation and migration of rat vascular smooth muscle cells (VSMCs), and to explore the underlying mechanisms. VSMCs were pretreated with alisol A 24-acetate and a specific extracellular signal-regulated kinase (ERK) inhibitor, U0126, and then stimulated with 50 mg/l Ox-LDL in vitro. The expression of VSMC phenotypic marker SM22α was determined using immunocytochemistry, and the migration of VSMCs was detected using a scratch-wound healing assay. The expression of matrix metalloproteinase (MMP)-9, MMP-2, phosphorylated ERK1/2 (pERK1/2) and total ERK was determined. Ox-LDL treatment caused a reduction in SM22α expression, VSMC transformation to the synthetic phenotype, increased MMP-2 and MMP-9 synthesis, the extension of VSMC migration distance and the upregulation of pERK1/2 expression, while the addition of alisol A 24-acetate or U0126 resulted in the elevation of SM22α expression, VSMC transformation to the contractile phenotype, a reduction in MMP-2 and MMP-9 expression, the shortening of cell migration distance and decreased pERK1/2 expression. The results of this study demonstrate that alisol A 24-acetate effectively reverses the phenotypic transformation and inhibits the migration of VSMCs, which may be associated with the suppression of the ERK1/2 signaling pathway.

Dynamic remodeling of endometrial extracellular matrix regulates embryo receptivity in cattle

We aimed to evaluate in the bovine endometrium whether (1) key genes involved in endometrial extracellular matrix (ECM) remodeling are regulated by the endocrine peri-ovulatory milieu; and (2) specific endometrial ECM-related transcriptome can be linked to pregnancy outcome. In Experiment 1, pre-ovulatory follicle growth of cows was manipulated to obtain two groups with specific endocrine peri-ovulatory profiles: the Large Follicle-Large CL group (LF-LCL) served as a paradigm for greater receptivity and fertility and showed greater plasma pre-ovulatory estradiol and post-ovulatory progesterone concentrations when compared to the Small Follicle-Small CL group (SF-SCL). Endometrium was collected on days 4 and 7 of the estrous cycle. Histology revealed a greater abundance of total collagen content in SF-SCL on day 4 endometrium. In Experiment 2, cows were artificially inseminated and, six days later, endometrial biopsies were collected. Cows were retrospectively divided into pregnant and non-pregnant (P vs. NP) groups after diagnosis on day 30. In both experiments, expression of genes related to ECM remodeling in the endometrium was studied by RNAseq and qPCR. Gene ontology analysis showed an inhibition in the expression of ECM-related genes in the high receptivity groups (LF-LCL and P). Specifically, there was down-regulation of TGFB2, ADAMTS2, 5 and 14, TIMP3 and COL1A2, COL3A1, COL7A1 and COL3A3 in the LF-LCL and P groups. In summary, the overlapping set of genes differently expressed in both fertility models: (1) suggests that disregulation of ECM remodeling can impair receptivity and (2) can be used as markers to predict pregnancy outcome in cattle.

Barnidipine compared to lercanidipine in addition to losartan on endothelial damage and oxidative stress parameters in patients with hypertension and type 2 diabetes mellitus

Background

Essential hypertension has been extensively reported to cause endothelial dysfunction. The aim of this study was to evaluate the effects of barnidipine or lercanidipine, in addition to losartan, on some parameters indicative of endothelial damage and oxidative stress in hypertensive, type 2 diabetic patients.

Methods

One hundred and fifty one patients were randomised to barnidipine, 20 mg/day, or lercanidipine, 20 mg/day, both in addition to losartan, 100 mg/day, for 6 months. We assessed BP every month, in addition, patients underwent ambulatory blood pressure monitoring (ABPM). We also assessed: fasting plasma glucose (FPG), glycated hemoglobin (HbA_1c), some markers such as high-sensitivity C-reactive protein (Hs-CRP), tumor necrosis factor-α (TNF-α), metalloproteinase-2 (MMP-2) and -9 (MMP-9), soluble vascular adhesion protein-1 (sVCAM-1), soluble intercellular adhesion protein-1 (sICAM-1), isoprostanes and paraoxonase-1 (PON-1).

Results

Both barnidipine and lercanidipine resulted in a significant reduction in blood pressure, even if the reduction obtained with barnidipine + losartan was greater than that obtained with lercanidipine + losartan. Data recorded with ABPM also showed a similar trend. Barnidipine + losartan reduced the levels of Hs-CRP, TNF-α, sVCAM-1, sICAM-1, and isoprostanes both compared to baseline and to lercanidipine + losartan.

Conclusions

Barnidipine + losartan gave an improvement of some parameters indicative of endothelial damage and oxidative stress in diabetic and hypertensive patients.

Trial registration

NCT02064218, ClinicalTrials.gov

Abdominal aortic aneurysm and histological, clinical, radiological correlation

To date, the pathogenesis of abdominal aortic aneurism (AAA) still remains unclear. As such, the aim of this study was to evaluate changes of the aortic structure during AAA. We analysed the microscopic frame of vessels sections, starting from the primum movens leading to abnormal dilatation. AAA samples were collected and processed through various staining methods (Verhoeff-Van Gieson, Masson Goldner, Sirius Red). Subsequently, the vessel morphology and collagenic web of the tunica media and adventitia were determined and the amount of type I and type III collagen was measured. We also applied immune-histochemistry markers for CD34 and PGP 9.5 in order to identify vascular and nerve structures in the aorta. Immune-positivity quantification was used to calculate the percentage of the stained area. We found increasing deposition of type I collagen and reduced type III collagen in both tunica media and adventitia of AAA. The total amount of vasa vasorum, marked with CD34, and nerva vasorum, marked with PGP 9.5, was also higher in AAA samples. Cardiovascular risk factors (blood pressure, dyslipidemia, cigarette smoking) and radiological data (maximum aneurism diameter, intra-luminal thrombus, aortic wall calcification) increased these changes. These results suggest that the tunica adventitia may have a central role in the pathogenesis of AAA as clearly there are major changes characterized by rooted inflammatory infiltration. The presence of immune components could explain these modifications within the framework of the aorta.

Bicuspid aortic valve hemodynamics does not promote remodeling in porcine aortic wall concavity

AIM: To investigate the role of type-I left-right bicuspid aortic valve (LR-BAV) hemodynamic stresses in the remodeling of the thoracic ascending aorta (AA) concavity, in the absence of underlying genetic or structural defects.

METHODS: Transient wall shear stress (WSS) profiles in the concavity of tricuspid aortic valve (TAV) and LR-BAV AAs were obtained computationally. Tissue specimens excised from the concavity of normal (non-dilated) porcine AAs were subjected for 48 h to those stress environments using a shear stress bioreactor. Tissue remodeling was characterized in terms of matrix metalloproteinase (MMP) expression and activity via immunostaining and gelatin zymography.

RESULTS: Immunostaining semi-quantification results indicated no significant difference in MMP-2 and MMP-9 expression between the tissue groups exposed to TAV and LR-BAV AA WSS (P = 0.80 and P = 0.19, respectively). Zymography densitometry revealed no difference in MMP-2 activity (total activity, active form and latent form) between the groups subjected to TAV AA and LR-BAV AA WSS (P = 0.08, P = 0.15 and P = 0.59, respectively).

CONCLUSION: The hemodynamic stress environment present in the concavity of type-I LR-BAV AA does not cause any significant change in proteolytic enzyme expression and activity as compared to that present in the TAV AA.

Cellular prion protein regulates invasion and migration of breast cancer cells through MMP-9 activity

Function of cellular prion protein (PrP(c)) in cancer progression has not been elucidated yet. Ectopic expression of PrP(c) increases the invasion and migration of breast cancer cell line, MCF-7 cells. Overexpressed PrP(c) increases matrix metalloprotease-9 (MMP-9) expression by enhancing association of NF-κB in promoter of MMP-9 gene and ERK signaling in MCF-7 cells. Whereas, silencing of PrP(c) by siRNA suppresses ERK activation and MMP-9 expression resulting the down-regulation of MD-MB231 cell migration and invasion. Overall, these results suggest that PrP(c) contribute the breast cancer invasion and migration via MMP-9.

High prevalence of cardiovascular risk factors in children and adolescents with Williams-Beuren syndrome

Background

A high incidence of cardiovascular (CV) risk factors has been reported in adults with Williams-Beuren syndrome (WS). However, the prevalence of these factors in children and adolescents with WS is unknown. Therefore, the purpose of this study was to evaluate the prevalence of CV risk factors in these patients.

Methods

Thirty-two WS patients aged <18 years were enrolled in the study. Oxidized low-density lipoprotein levels (n = 32), oral glucose tolerance test results (n = 20), plasma renin and aldosterone levels (n = 31), 24-h ambulatory blood pressure (ABP; n = 24), carotid artery intima-media thickness (IMT; n = 15), and brachial artery flow-mediated dilatation (FMD; n = 15) were measured and analyzed.

Results

The lipid profile revealed hypercholesterolemia in 22 % and elevated oxidized low-density lipoprotein levels in 94 % of the patients. Glucose metabolism abnormalities were found in 70 % of the patients. Insulin resistance was observed in 40 % of the patients. High plasma renin and aldosterone levels were detected in 45 and 39 % of the patients, respectively. A mean systolic blood pressure above the 90th percentile was noted in 29 % of patients. High IMT (>0.65 mm) and low FMD (<9 %) were detected in 80 and 73 % of patients, respectively.

Conclusion

In patients with WS, CV risk factors are frequently present from childhood. In children with WS, screening tests for the early detection of CV risk factors and long-term follow-up are required to determine whether long-term exposure to these factors increases the risk for CV events in adulthood.

Atorvastatin and sildenafil decrease vascular TGF-β levels and MMP-2 activity and ameliorate arterial remodeling in a model of renovascular hypertension

Imbalanced matrix metalloproteinase (MMP)-2 activity and transforming growth factor expression (TGF-β) are involved in vascular remodeling of hypertension. Atorvastatin and sildenafil exert antioxidant and pleiotropic effects that may result in cardiovascular protection. We hypothesized that atorvastatin and sildenafil alone or in association exert antiproliferative effects by down-regulating MMP-2 and TGF-β, thus reducing the vascular hypertrophy induced by two kidney, one clip (2K1C) hypertension.

Sham and 2K1C rats were treated with oral atorvastatin 50 mg/kg, sildenafil 45 mg/kg, or both, daily for 8 weeks. Blood pressure was monitored weekly. Morphologic changes in the aortas were studied. TGF-β levels were determined by immunofluorescence. MMP-2 activity and expression were determined by in situ zymography, gel zymography, Western blotting, and immunofluorescence. The effects of both drugs on proliferative responses of aortic smooth muscle cells to PDGF and on on MMP-2 activity in vitro were determined. Atorvastatin, sildenafil, or both drugs exerted antiproliferative effects in vitro. All treatments attenuated 2K1C-induced hypertension and prevented the increases in the aortic cross-sectional area and media/lumen ratio in 2K1C rats. Aortas from 2K1C rats showed higher collagen deposition, TGF-β levels and MMP-2 activity and expression when compared with Sham-operated animals. Treatment with atorvastatin and/or sildenafil was associated with attenuation of 2K1C hypertension-induced increases in these pro-fibrotic factors. However, these drugs had no in vitro effects on hr-MMP-2 activity.

Atorvastatin and sildenafil was associated with decreased vascular TGF-β levels and MMP-2 activity in renovascular hypertensive rats, thus ameliorating the vascular remodeling. These novel pleiotropic effects of both drugs may translate into protective effects in patients.

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Atorvastatin and sildenafil exert antioxidant and other pleotropic effects.

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Imbalanced MMP-2 activity and TGF-β expression promote vascular remodeling in hypertension.

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Atorvastatin and sildenafil exerted antiproliferative effects in vitro.

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Both drugs prevented hypertension-induced increases pro-fibrotic factors.

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These additional pleiotropic effects may translate into protective effects in patients.

Role of MMP-2 and MMP-9 in resistance to drug therapy in patients with resistant hypertension

Background

Despite the increased evidence of the important role of matrix metalloproteinases (MMP-9 and MMP‑2) in the pathophysiology of hypertension, the profile of these molecules in resistant hypertension (RHTN) remains unknown.

Objectives

To compare the plasma levels of MMP-9 and MMP-2 and of their tissue inhibitors (TIMP-1 and TIMP-2, respectively), as well as their MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios, between patients with controlled RHTN (CRHTN, n=41) and uncontrolled RHTN (UCRHTN, n=35). In addition, the association of those parameters with clinical characteristics, office blood pressure (BP) and arterial stiffness (determined by pulse wave velocity) was evaluate in those subgroups.

Methods

This study included 76 individuals diagnosed with RHTN and submitted to physical examination, electrocardiogram, and laboratory tests to assess biochemical parameters.

Results

Similar values of MMP-9, MMP-2, TIMP-1, TIMP-2, and MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios were found in the UCRHTN and CRHTN subgroups (P>0.05). A significant correlation was found between diastolic BP (DBP) and MMP-9/TIMP-1 ratio (r=0.37; P=0.02) and DPB and MMP-2 (r=-0.40; P=0.02) in the UCRHTN subgroup. On the other hand, no correlation was observed in the CRHTN subgroup. Logistic regression models demonstrated that MMP-9, MMP-2, TIMP-1, TIMP-2 and their ratios were not associated with the lack of BP control.

Conclusion

These findings suggest that neither MMP-2 nor MMP-9 affect BP control in RHTN subjects.

ADAMTS-7 promotes vascular smooth muscle cells proliferation in vitro and in vivo

Vascular smooth muscle cell (VSMC) proliferation and migration are pivotal for the pathogenesis of atherosclerosis and post-angioplasty restenosis. We have recently reported that a disintegrin and metalloproteinase with thrombospondin motifs-7 (ADAMTS-7), a novel metalloproteinase, contributes directly to neointima formation by mediating VSMC migration. However, whether ADAMTS-7 affects VSMC proliferation remains unclear. In this study, we found that luminal adenoviral delivery of ADAMTS-7 aggravated intimal hyperplasia 7 d after injury, paralleled by an increased percentage of PCNA-positive cells in both intima and media. In contrast, perivascular administration of ADAMTS-7 siRNA, but not scrambled siRNA to injured arteries attenuated intimal thickening at day 7, paralleled with reduced intimal VSMC replication, without alteration of VSMC proliferation in the media. In accordance, [(3)H]-thymidine incorporation assay in primary cultured rat VSMCs revealed an enhanced replication rate (by 61%) upon ADAMTS-7 overexpression and retarded proliferation (by 23%) upon ADAMTS-7 siRNA administration. Our data demonstrates that ADAMTS-7 promotes VSMC proliferation both in vitro and in vivo. ADAMTS-7 may therefore serve as a novel therapeutic target for atherosclerosis and post-angioplasty restenosis.

Adult vascular wall resident multipotent vascular stem cells, matrix metalloproteinases, and arterial aneurysms

Evidences have shown the presence of multipotent stem cells (SCs) at sites of arterial aneurysms: they can differentiate into smooth muscle cells (SMCs) and are activated after residing in a quiescent state in the vascular wall. Recent studies have implicated the role of matrix metalloproteinases in the pathogenesis of arterial aneurysms: in fact the increased synthesis of MMPs by arterial SMCs is thought to be a pivotal mechanism in aneurysm formation. The factors and signaling pathways involved in regulating wall resident SC recruitment, survival, proliferation, growth factor production, and differentiation may be also related to selective expression of different MMPs. This review explores the relationship between adult vascular wall resident multipotent vascular SCs, MMPs, and arterial aneurysms.

Specific matrix metalloproteinases play different roles in intraplaque angiogenesis and plaque instability in rabbits

BACKGROUND

Ectopic angiogenesis within the intima and media is considered to be a hallmark of advanced vulnerable atherosclerotic lesions. Some studies have shown that specific matrix metalloproteinases (MMPs) might play different roles in angiogenesis. Therefore, we investigated the predominant effects of specific MMPs in intraplaque angiogenesis and plaque instability in a rabbit model of atherosclerosis.

METHODS AND RESULTS

New Zealand rabbits underwent balloon injury of the abdominal artery and ingestion of a high-cholesterol (1%) diet to establish an atherosclerotic animal model. At weeks 4, 6, 8, 10, and 12 after balloon injury, five rabbits were euthanized and the abdominal aorta was harvested. Blood lipid analysis, intravascular ultrasound imaging, pathologic and immunohistochemical expression studies, and western blotting were performed. From weeks 4 to 12, the expression of MMP-1, -2, -3, and -9 and vascular endothelial growth factor A (VEGF-A) increased with atherosclerotic plaque development in the abdominal aorta, while the expression of MMP-14 substantially decreased. The vulnerability index (VI) gradually increased over time. Intraplaque neovessels appeared at week 8. The microvessel density (MVD) was greater at week 12 than at week 8. The VI, MVD, and VEGF-A level were positively correlated with the MMP-1, -2,-3, and -9 levels within plaques. Negative correlations were noted between the MMP-14 level and the VI, MVD, and VEGF-A level.

CONCLUSION

Upregulation of MMP-1, -2, -3, and -9 and downregulation of MMP-14 may contribute to intraplaque angiogenesis and plaque instability at the advanced stage of atherosclerosis in rabbits.

Cardiovascular remodelling in coronary artery disease and heart failure

Remodelling is a response of the myocardium and vasculature to a range of potentially noxious haemodynamic, metabolic, and inflammatory stimuli. Remodelling is initially functional, compensatory, and adaptive but, when sustained, progresses to structural changes that become self-perpetuating and pathogenic. Remodelling involves responses not only of the cardiomyocytes, endothelium, and vascular smooth muscle cells, but also of interstitial cells and matrix. In this Review we characterise the remodelling processes in atherosclerosis, vascular and myocardial ischaemia-reperfusion injury, and heart failure, and we draw attention to potential avenues for innovative therapeutic approaches, including conditioning and metabolic strategies.

In vitro anti-proliferative and anti-angiogenic activities of thalidomide dithiocarbamate analogs

Inhibition of angiogenesis is currently perceived as a promising strategy in the treatment of cancer. The anti-angiogenicity of thalidomide has inspired a second wave of research on this teratogenic drug. The present study aimed to investigate the anti-proliferative and anti-angiogenic activities of two thalidomide dithiocarbamate analogs by studying their anti-proliferative effects on human umbilical vein endothelial cells (HUVECs) and MDA-MB-231 human breast cancer cell lines. Their action on the expression levels of IL-6, IL-8, TNF-α, VEGF165, and MMP-2 was also assessed. Furthermore, their effect on angiogenesis was evaluated through wound healing, migration, tube formation, and nitric oxide (NO) assays. Results illustrated that the proliferation of HUVECs and MDA-MB-231 cells was not significantly affected by thalidomide at 6.25-100μM. Thalidomide failed to block angiogenesis at similar concentrations. By contrast, thalidomide dithiocarbamate analogs exhibited significant anti-proliferative action on HUVECs and MDA-MB-231 cells without causing cytotoxicity and also showed powerful anti-angiogenicity in wound healing, migration, tube formation, and NO assays. Thalidomide analogs 1 and 2 demonstrated more potent activity to suppress expression levels of IL-6, IL-8, TNF-α, VEGF165, and MMP-2 than thalidomide. Analog 1 consistently, showed the highest potency and efficacy in all the assays. Taken together, our results support further development and evaluation of novel thalidomide analogs as anti-tumor and anti-angiogenic agents.

Nanoparticle targeting to diseased vasculature for imaging and therapy

Significant challenges remain in targeting drugs to diseased vasculature; most important being rapid blood flow with high shear, limited availability of stable targets, and heterogeneity and recycling of cellular markers. We developed nanoparticles (NPs) to target degraded elastic lamina, a consistent pathological feature in vascular diseases. In-vitro organ and cell culture experiments demonstrated that these NPs were not taken up by cells, but instead retained within the extracellular space; NP binding was proportional to the extent of elastic lamina damage. With three well-established rodent models of vascular diseases such as aortic aneurysm (calcium chloride mediated aortic injury in rats), atherosclerosis (fat-fed apoE-/- mice), and vascular calcification (warfarin + vitamin K injections in rats), we show precise NPs spatial targeting to degraded vascular elastic lamina while sparing healthy vasculature when NPs were delivered systemically. Nanoparticle targeting degraded elastic lamina is attractive to deliver therapeutic or imaging agents to the diseased vasculature.

FROM THE CLINICAL EDITOR

This novel work focuses on nanoparticle targeting of degraded elastic lamina in a variety of diseases, including atherosclerosis, vascular calcification, and aneurysm formation, and demonstrates the feasibility to deliver therapeutic or imaging agents to the diseased vasculature.

Hepatic apoptosis can modulate liver fibrosis through TIMP1 pathway

Apoptotic injury participates in hepatic fibrosis, but the molecular mechanisms are not well understood. The present study aimed to investigate the role of inducible TIMP1 in the pathogenesis of hepatic apoptosis-fibrosis. Apoptosis was induced with GCDC, LPS, and alcohol in precision-cut liver slices or bile duct ligation (BDL) in rats, as reflected by caspase-3 activity, TUNEL assay, and apoptosis-related gene profiles. The hepatic fibrosis was detected with Picrosirius staining, hydroxyproline determination, and expression profiling of fibrosis-related genes. Levels of TIMP1 were upregulated by the hepatic apoptosis, but downregulated by caspase inhibitor. The inducible TIMP1 was apoptosis-dependent. Once TIMP1 was inhibited with treatment of TIMP1-siRNA, the fibrotic response was reduced as demonstrated by hydroxyproline assay. In addition, the expression of fibrosis-related genes aSMA, CTGF, and TGFb2r were down-regulated subsequent to the treatment of TIMP1-siRNA. TIMP1 could mediate the expression of fibrosis-related genes. TIMP1 was transcriptionally regulated by nuclear factor c-Jun as demonstrated by EMSA and ChIP assay. The treatment of c-Jun siRNA could significantly decrease the expression of TIMP1 induced by alcohol, GCDC, or LPS treatment. Hepatic apoptosis induces the expression of TIMP1. Inducible TIMP1 can modulate the expression of fibrosis-related genes in liver. TIMP1 pathway is a potential target for therapeutic intervention of fibrotic liver diseases.

Genetic variants associated with circulating MMP1 levels near matrix metalloproteinase genes on chromosome 11q21-22 in Taiwanese: interaction with obesity

BACKGROUND

MMP1 is implicated in the pathogenesis of atherothrombotic cardiovascular disease. We aimed to elucidate genetic determinants of inflammatory marker levels, including circulating MMP1, in Taiwanese, and their association with obesity.

METHODS

Five genetic polymorphisms around matrix metalloproteinase genes on chromosome 11q21-22 region were genotyped in 519 subjects.

RESULTS

After adjusting for clinical covariates, two polymorphisms were significantly associated with MMP1 levels, rs1799750 and rs495366, using an additive inheritance model (P = 1.5x10-4 and P = 2.57x10-5, respectively). Using dominant model, minor alleles of rs1799750 and rs495366 were associated with higher MMP1 levels (P = 1.3x10-4 and P = 1.95x10-5, respectively). In haplotype analysis, two haplotypes inferred from five SNPs (A2GATA and A1GATG) were associated with MMP1 levels (P = 5x10-4 and P = 8.47x10-5, respectively). Subgroup and interaction analysis revealed an association of rs1799750 and rs495366 with MMP1 levels only in non-obese subjects (P = 6.66x10-6 and P = 4.38x10-5, respectively, and interaction P = 0.008 for rs1799750). Haplotype interaction analysis also showed significant interaction for haplotype A1GATG (interaction P = 0.003).

CONCLUSIONS

Genotypes/haplotypes around MMP1 locus are associated with MMP1 levels in Taiwanese. Further, since genotypes/haplotypes near MMP1 locus interact with obesity to set MMP1 levels, genetic determinants for MMP1 level may be different between obese and non-obese individuals.

The pseudopeptide HB-19 binds to cell surface nucleolin and inhibits angiogenesis

Background

Nucleolin is a protein over-expressed on the surface of tumor and endothelial cells. Recent studies have underlined the involvement of cell surface nucleolin in tumor growth and angiogenesis. This cell surface molecule serves as a receptor for various ligands implicated in pathophysiological processes such as growth factors, cell adhesion molecules like integrins, selectins or laminin-1, lipoproteins and viruses (HIV and coxsackie B). HB-19 is a synthetic multimeric pseudopeptide that binds cell surface expressed nucleolin and inhibits both tumor growth and angiogenesis.

Methodology/principal findings

In the present work, we further investigated the biological actions of pseudopeptide HB-19 on HUVECs. In a previous work, we have shown that HB-19 inhibits the in vivo angiogenesis on the chicken embryo CAM assay. We now provide evidence that HB-19 inhibits the in vitro adhesion, migration and proliferation of HUVECs without inducing their apoptosis. The above biological actions seem to be regulated by SRC, ERK1/2, AKT and FAK kinases as we found that HB-19 inhibits their activation in HUVECs. Matrix metalloproteinases (MMPs) play crucial roles in tumor growth and angiogenesis, so we investigated the effect of HB-19 on the expression of MMP-2 and we found that HB-19 downregulates MMP-2 in HUVECs. Finally, down regulation of nucleolin using siRNA confirmed the implication of nucleolin in the biological actions of these peptides.

Conclusions/significance

Taken together, these results indicate that HB-19 could constitute an interesting tool for tumor therapy strategy, targeting cell surface nucleolin.

Nucleolin mediates the antiangiogenesis effect of the pseudopeptide N6L

BACKGROUND

Nucleolin is a protein over-expressed on the surface of activated cells. Recent studies have underlined the involvement of cell surface nucleolin in angiogenesis processes. This cell surface molecule serves as a receptor for various ligands implicated in pathophysiological processes such as growth factors, cell adhesion molecules like integrins, selectins or laminin-1, lipoproteins and viruses. N6L is a synthetic multimeric pseudopeptide that binds cell surface expressed nucleolin and inhibits cell proliferation.

RESULTS

In the present work, we further investigated the mechanisms of action of pseudopeptide N6L on angiogenesis using HUVECs. We provide evidence that N6L inhibits the in vitro adhesion, proliferation and migration of HUVECs without inducing their apoptosis. In addition, we found that N6L downregulates MMP-2 in HUVECs. The above biological actions are regulated by SRC, ERK1/2, AKT and FAK kinases as we found that N6L inhibits their activation in HUVECs. Finally, down regulation of nucleolin using siRNA demonstrated the implication of nucleolin in the biological actions of these peptides.

CONCLUSIONS

Taken together, these results indicate that N6L could constitute an interesting therapeutic tool for treating diseases associated with excessive angiogenesis.

Gene therapy for cardiovascular disease: perspectives and potential

Cardiovascular disease is the most frequent cause of mortality in the western world, accounting for over 800,000 premature deaths per year in the EU alone. Cardiovascular disease is the second most common application for gene therapy clinical trials, which most frequently employ adenovirus serotype 5 (Ad5)-based vectors as delivery vehicles. Although interactions of Ad5 vectors with circulating proteins and cells can limit their efficacy after systemic administration, local gene delivery strategies show great potential in the cardiovascular setting, notably in the context of vascular delivery. Here we review the pathogenesis of bypass graft failure and in-stent restenosis, identifying potential therapeutic targets and discussing recent advances in the field of adenovirus biology and retargeting that, in concert, will potentially translate in coming years to more effective gene therapies for cardiovascular applications.

Anti-inflammatory properties of sirtuin 6 in human umbilical vein endothelial cells

A prominent feature of inflammatory diseases is endothelial dysfunction. Factors associated with endothelial dysfunction include proinflammatory cytokines, adhesion molecules, and matrix degrading enzymes. At the transcriptional level, they are regulated by the histone deacetylase sirtuin (SIRT) 1 via its actions on the proinflammatory transcription factor nuclear factor-κB (NF-κB). The role of SIRT6, also a histone deacetylase, in regulating inflammation in endothelial cells is not known. The aim of this study was to determine the effect of SIRT6 knockdown on inflammatory markers in human umbilical vein endothelial cells (HUVECs) in the presence of lipopolysaccharide (LPS). LPS decreased expression of SIRT6 in HUVECs. Knockdown of SIRT6 increased the expression of proinflammatory cytokines (IL-1β, IL-6, IL-8), COX-prostaglandin system, ECM remodelling enzymes (MMP-2, MMP-9 and PAI-1), the adhesion molecule ICAM-1, and proangiogenic growth factors VEGF and FGF-2; cell migration; cell adhesion to leukocytes. Loss of SIRT6 increased the expression of NF-κB, whereas overexpression of SIRT6 was associated with decreased NF-κB transcriptional activity. Taken together, these results demonstrate that the loss of SIRT6 in endothelial cells is associated with upregulation of genes involved in inflammation, vascular remodelling, and angiogenesis. SIRT6 may be a potential pharmacological target for inflammatory vascular diseases.

Possible mechanical roles of glycosaminoglycans in thoracic aortic dissection and associations with dysregulated transforming growth factor-β

BACKGROUND

Four distinguishing histopathological characteristics of thoracic aortic aneurysms and dissections (TAADs) are the fragmentation or degradation of elastic fibers, loss of smooth muscle, pooling of glycosaminoglycans, and remodeling of fibrillar collagens. Of these, pooling of glycosaminoglycans appears to be unique to these lesions.

METHODS

This review acknowledges the importance of dysregulated transforming growth factor-β (TGF-β) in TAADs and offers a complementary hypothesis that increased TGF-β could contribute to the accumulation of glycosaminoglycans in the media of the proximal thoracic aorta. Regardless, observed pools of glycosaminoglycans could decrease tensile strength, cause stress concentrations, and increase intralamellar swelling pressure, all of which could initiate local delaminations that could subsequently propagate as dissections and result in a false lumen or rupture.

CONCLUSIONS

There is a pressing need to investigate potential mechanical as well as biological consequences of accumulated glycosaminoglycans in TAADs and to elucidate responsible signaling pathways, with particular attention to synthetic cells of nonmesodermal lineage. Such research could provide insight into the mechanisms of dissection and the seemingly paradoxical role of the over-expression of a cytokine that is typically associated with fibrosis but is implicated in a degenerative disease of the aorta that can result in a catastrophic mechanical failure.

The effects of PPARγ agonist rosiglitazone on neointimal hyperplasia in rabbit carotid anastomosis model

Background

Neointimal hyperplasia involving smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) degradation is an important component of atherosclerosis. It develops as a response to vascular injury after balloon angioplasty and vascular graft placement. Matrix metalloproteinases (MMPs) induce SMC proliferation, migration and contribute to intimal hyperplasia by degrading ECM. PPARγ agonists inhibit SMC proliferation, migration and lesion formation. In this study, we aimed to investigate the effects of PPARγ agonist rosiglitazone on neointimal hyperplasia and gelatinase (MMP-2 and MMP-9) expressions in rabbit carotid anastomosis model.

Methods

New Zealand white rabbits (n = 13, 2.7–3.2 kg) were divided into placebo and treatment groups. Right carotid artery (CA) was transected and both ends were anastomosed. Treatment group (n = 6) received rosiglitazone (3 mg/kg/day/p.o.) and placebo group (n = 7) received PBS (phosphate buffered saline, 2.5 ml/kg/day/p.o.) for 4 weeks postoperatively. After the sacrification, right and left CAs were isolated. Morphometric analyses and immunohistochemical examinations for gelatinases were performed.

Results

Intimal area (0.055 ± 0.005 control vs 0.291 ± 0.020 μm² anastomosed, p < 0,05) and index (0.117 ± 0.002 control vs 0.574 ± 0.013 anastomosed, p < 0,01) significantly increased in anastomosed arteries compared to control arteries from placebo group. However, in rosiglitazone-treated group, intimal area (0.291 ± 0.020 PBS vs 0.143 ± 0.027 rosiglitazone, p < 0,05) and index (0.574 ± 0.013 PBS vs 0.263 ± 0.0078 rosiglitazone, p < 0,01) significantly decreased. Furthermore, gelatinase immunopositivity was found to have significantly increased in anastomosed arteries from placebo group and decreased with rosiglitazone treatment.

Conclusions

These results suggest that rosiglitazone may prevent neointimal hyperplasia, which is the most important factor involved in late graft failure, by inhibiting gelatinase enzyme expression.

In silico scaffold evaluation and solid phase approach to identify new gelatinase inhibitors

Among matrix metalloproteinases (MMPs), gelatinases MMP-2 (gelatinase A) and MMP-9 (gelatinase B) play a key role in a number of physiological processes such as tissue repair and fibrosis. Many evidences point out their involvement in a series of pathological events, such as arthritis, multiple sclerosis, cardiovascular diseases, inflammatory processes and tumor progression by degradation of the extracellular matrix. To date, the identification of non-specific MMP inhibitors has made difficult the selective targeting of gelatinases. In this work we report the identification, design and synthesis of new gelatinase inhibitors with appropriate drug-like properties and good profile in terms of affinity and selectivity. By a detailed in silico protocol and innovative and versatile solid phase approaches, a series of 4-thiazolydinyl-N-hydroxycarboxyamide derivatives were identified. In particular, compounds 9a and 10a showed a potent inhibitory activity against gelatinase B and good selectivity over the other MMP considered in this study. The identified compounds could represent novel potential candidates as therapeutic agents.

Effect of metformin on the proliferation, migration, and MMP-2 and -9 expression of human umbilical vein endothelial cells

Recent epidemiological studies have demonstrated that metformin lowers the risk of several types of cancer in diabetic patients. Matrix metalloproteinases (MMPs) play a crucial role in the degradation of the vascular basement membrane extracellular matrix proteins, thereby promoting endothelial cell invasion, migration and angiogenesis in the incidence and progression of tumors. The aim of this study was to investigate the effects of metformin on human umbilical vein endothelial cell (HUVEC) proliferation and migration, as well as on MMP-2 and MMP-9 expression. Cell proliferation was determined by cell counting and MTT colorimetric assays. Cell migration was assessed by the wound repair method. Quantitative real-time reverse transcription PCR was performed to quantify the mRNA expression of MMPs. Metformin at concentrations of 0.5–3.0 mM effectively reduced the number of endothelial cells by 5.5–55%, without being cytotoxic to the cells. Similarly, cell proliferation and migration were markedly inhibited by metformin. In addition, treatment with metformin demonstrated a strong (P<0.001) suppressive effect on the mRNA levels of MMP-2 and -9 in the endothelial cells. The inhibitory effects of metformin on endothelial cell number, migration, and MMP expression were reversed partially by compound C, which is an inhibitor of AMP-activated protein kinase (AMPK). The present study reports that metformin considerably inhibited the proliferation, migration, and MMP-2 and -9 expression of HUVECs, and the effect was partially AMPK-dependent. The obtained findings provide a molecular rationale, whereby metformin can exert anticancer effects.

Novel therapies targeting endometriosis

Endometriosis is an often painful disorder in which the endometrial glands and stroma grow outside the uterus. The disease affects women's quality of life and is a common cause of infertility. In this review, we describe promising new developments in the field based on in vitro assays and rodent models, each of which has the potential to be beneficial in the treatment of this disease. We will specifically describe the role of anti-inflammatory drugs, selective estrogen, or progesterone modulators, statins, antiangiogenic agents, and the potential for targeting stem cells as likely methods to hone in and eliminate endometriosis. The most promising of these potential therapies are currently slated for further testing in both rodent and nonhuman primate trials.